Image projection apparatus and presentation system

ABSTRACT

The present invention is concerning an image projection apparatus comprising: a projecting unit that projects and displays on a projection surface each image in a time sharing manner for each of a plurality of color components, for an input image signal; a shooting unit that shoots a projected image on the projection surface; a shoot control unit that makes the shooting unit perform the shooting, when a detection mode of a irradiation point at which light is irradiated from an irradiation device on the projection surface is set, in timing shifted by a certain amount of time from a synchronized state to time sharing timing of each color component in the projecting unit; and an irradiation-point-position detecting unit that detects, from a projected image projected by the projecting unit, a position of the irradiation point on the image.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by referencethe entire contents of Japanese Patent Application No. 2013-168415 filedin Japan on Aug. 14, 2013.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image projection apparatus and apresentation system, and more specifically, to an image projectionapparatus that converts image data to an optical image to project on aprojection surface (screen) in an enlarged manner, and a presentationsystem to perform presentation, for example, pointing by irradiationlight from an irradiation device (laser pointer and the like) on aprojected image on the projection surface.

2. Description of the Related Art

Projectors project images such as characters and graphs on a screen(projection surface) in an enlarged manner, and therefore, are widelyused in presentations to a number of people and the like. In such apresentation, a presenter (user) sometimes uses a laser pointer, aninfrared laser pointer, or the like to point an image projected on ascreen to make explanation easy to understand. However, in such a case,because a point that is pointed by the pointer moves as the handoperating the pointer moves, an exact pointed position can be unclear topeople that are looking at the projected image. To solve the problem, atechnique in which a point irradiated with an infrared laser pointer bya user is detected by a charge coupled device (CCD) camera that isequipped in a projector, and a pointer image is displayed at the samepoint (position) as this irradiation point (irradiation position) hasbeen known (for example, Japanese Laid-open Patent Publication No.11-271675).

However, when a laser pointer is used, if detection of a pointirradiated by the laser pointer from a picture captured by a camera isconsidered similarly to Japanese Laid-open Patent Publication No.11-271675, and if color and brightness of the projected picture aresimilar to color of the laser pointer, there is a possibility that theirradiation point of the laser pointer cannot be detected depending on aprojected image. Particularly, for a digital light processing (DLP)(registered trademark) projector, there is a possibility that anirradiation point cannot be detected stably because of influence ofleakage light from an adjacent filter segment in a different color in acolor wheel.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

According to the present invention, there is provided an imageprojection apparatus comprising: a projecting unit that projects anddisplays on a projection surface each image in a time sharing manner foreach of a plurality of color components, for an input image signal; ashooting unit that shoots a projected image on the projection surface; ashoot control unit that makes the shooting unit perform the shooting,when a detection mode of a irradiation point at which light isirradiated from an irradiation device on the projection surface is set,in timing shifted by a certain amount of time from a synchronized stateto time sharing timing of each color component in the projecting unit;and an irradiation-point-position detecting unit that detects, from aprojected image projected by the projecting unit, a position of theirradiation point on the image.

The present invention also provides a presentation system comprising: aprojecting unit that projects and displays, on a projection surface,each image in a time sharing manner for each of a plurality of colorcomponents, for an input image signal; a shooting unit that shoots aprojected image on the projection surface; an irradiation device thatforms an irradiation point by irradiating light onto the projectionsurface; a shoot control unit that makes the shooting unit perform theshooting, when a detection mode of a irradiation is set, in timingshifted by a certain amount of time from a synchronized state to timesharing timing of each color component in the projecting unit; and anirradiation-point-position detecting unit that detects, from theprojected image shot by the shooting unit, a position of the irradiationpoint on the image.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a configuration of a presentationsystem according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating a configuration of an opticalengine of a projector device that constitutes a part of the presentationsystem in FIG. 1;

FIG. 3 is a block diagram indicating a configuration of the projectordevice, particularly, functions that constitute a base control unit;

FIG. 4 is a diagram illustrating an example of a projection pattern forprojection conversion;

FIG. 5 is a diagram indicating seven segments of Cy-W-R-M-Y-G-Bconstituting a color wheel;

FIG. 6 is a diagram indicating a correlation between the seven segmentsof the color wheel and a camera-captured image when each segment isdisplayed on a projection surface;

FIG. 7A is a diagram indicating relation between seven color segments(one cycle) of the color wheel and projection light colors, and FIG. 7Bis an explanatory diagram of relation between a cycle of the color wheeland exposure time of a camera unit;

FIG. 8 is a diagram indicating an example of image data when laser beamsfrom red, green, and blue laser pointers are irradiated on one projectedimage;

FIG. 9 is a diagram indicating images of detected irradiation points oflaser beams when a projected image on which laser beams from red, green,and blue laser pointers are irradiated at Timing A, B, and C,respectively, is shot;

FIG. 10 is a diagram indicating relation among a rotation cycle of thecolor wheel, a shooting cycle of a camera, and shutter/exposure timingof the camera to detect a single color laser pointer;

FIG. 11 is a diagram indicating relation among a rotation cycle of thecolor wheel, a shooting cycle of a camera, and shutter/exposure timingof the camera to detect a multi-color laser pointer;

FIG. 12 is a flowchart indicating a process algorism of a drive controlunit of the projector device;

FIG. 13 is a diagram illustrating one projection mode to emphasize anirradiation point of the presentation system of the embodiment;

FIGS. 14(a) and 14(b) are diagrams illustrating another projection modesto emphasize an irradiation point of the projector device of thepresentation system of the embodiment; and

FIG. 15 is an explanatory diagram of another configuration of thepresentation system according to the present invention, and illustratesan example of a state of the projector device when a camera is removablyarranged.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of the present invention is explained below based on FIG.1 to FIG. 15. FIG. 1 illustrates a configuration of a presentationsystem 100 according to the embodiment.

The presentation system 100 includes, for example, as illustrated inFIG. 1, a projector device 10 as an image projection apparatus, apersonal computer (hereinafter “external PC”) 20 that is connectedthrough a cable (a high definition multimedia interface (HDMI)(registered trademark) cable, a video graphics array (VGA) cable, or ananalog red-green-blue (RGB) component video signal cable) or the like tobe an output source of presentation image data, and the like.

The projector device 10 converts image data such as a still image and amoving image input from the external PC 20 into an optical image, toproject on a screen 30 that is a projection surface. Not limited to theexternal PC 20, a still image, a moving image, and the like may be inputto the projector device 10 from a storage device such as a universalserial bus (USB) memory and a secure digital (SD) card.

Moreover, in the presentation system 100, the projector device 10 isintegrally equipped with a camera unit 22 as a shooting unit to shoot animage that is projected on the screen 30 as a projection area 35thereof.

The projector device 10 of this presentation system 100 stores apresentation control program to detect a position of an irradiationpoint of a laser beam from a laser pointer 40 on the projection area 35based on an image of the projection area 35 that is taken at a certainframe rate (for example, 30 frames/second) by the camera unit 22, and tocombine a pointer image and other emphasizing images at an appropriatepoint in the presentation image data based on the position of theirradiation point with the image to be projected, not just convertingpresentation image data from the external PC 20 into an optical image toproject in an enlarged manner according to an operation by a user. Anemphasizing image includes, for example, an under line, a box, and thelike.

A shooting range of a projected image on the screen 30 of the cameraunit 22 is only required to be a range that sufficiently includestherein the projection area 35, and is not necessarily required to fitexactly with the projection area 35.

The projector device 10 includes, thereinside, an optical engine unit 10a (see FIG. 2), and a base control unit 10 b (see FIG. 3) that performscontrol of video signals and control of the optical engine unit 10 a.

The optical engine unit 10 a includes an optical system 3 a and aprojection system 3 b as shown in FIG. 2. The optical system 3 aincludes a color wheel 5, a light tunnel 6, a relay lens 7, a flatmirror 8, a concave mirror 9, and an image forming unit 2. Each of thesecomponents is arranged in a main unit of the projector device 10.

The color wheel in a disc shape converts white light from a light source4 into light in RGB each of which repeats every unit time to be emittedto the light tunnel 6. As the light source 4, for example, ahigh-pressure mercury lamp is used in this example. The light source 4irradiates white light toward the optical system 3 a (the color wheel5). In the present embodiment, a lighting drive of the light source 4through a lamp power source 17, and a motor 18 (see FIG. 3) that drivesto rotate the color wheel 5 are both controlled by a drive control unit14 (see FIG. 3) described later.

To the color wheel 5, a black sticker as an index to detect a rotationposition thereof is arranged. The black sticker is detected by a markersensor 19 (see FIG. 3) as a detecting unit that is arranged adjacent toa peripheral end thereof, and thus a predetermined rotation position isdetected. A detection signal thereof is input to the drive control unit14. A detailed configuration of the color wheel 5 is described furtherlater.

The light tunnel 6 is formed in a cylindrical shape by putting sheetglasses together, and guides light emitted from the color wheel 5 to therelay lens 7.

The relay lens 7 is formed with two pieces of lenses in combination, andcorrects axial chromatic aberration of light emitted from the lighttunnel 6 to send the light to a reflection surface of the flat mirror 8.

The flat mirror 8 and the concave mirror 9 sequentially reflect lightemitted from the relay lens 7 to guide to the image forming unit 2.

That is, in the optical system 3 a, white light irradiated from thelight source 4 is separated into RGB, and guided to the image formingunit 2, as described above.

The image forming unit 2 is formed with multiple micro mirrors that areenabled to switch the position of inclination to each of an ON positionand an OFF position, and has a micro mirror array that can form a mirrorplane in a rectangular shape as a whole. As the mirror array, digitalmirror devices (DMD: registered trademark of Texas Instruments Inc.) areused in this example. In the image forming unit 2, each of the micromirrors is driven in time sharing drive based on data of video or animage, and projection light is processed so as to form predeterminedimage data to be reflected. The image forming unit 2 performs imageforming according to a modulation signal.

Furthermore, an OFF light plate that receives and absorbs unnecessarylight that is not used as projection light among incident light to theimage forming unit 2 is arranged above the image forming unit 2 in aperpendicular direction that is on a frontward side of the image formingunit 2 illustrated in FIG. 2 on a sheet. When light enters into theimage forming unit 2, the micro mirrors operate in a time sharing mannerby the action of the DMD devices based on video data, and light to beused is reflected toward the projection system 3 b by these micromirrors, and light to be discarded is reflected toward the OFF lightplate.

The projection system 3 b is formed with multiple lenses, and expandsthe video light from the image forming unit 2 with the lenses, toproject on the screen 30.

The base control unit 10 b includes various functional units such as avideo processing unit 12, a video-signal input-processing unit 13, thedrive control unit 14, an irradiation-point detecting unit 24 as anirradiation-point-position detecting unit, a conversion processing unit25, a conversion-coefficient calculating unit 26, and a pointergenerating unit 27 as indicated in a block diagram of the projectordevice 10 shown in FIG. 3.

These respective functional units are actually implemented by a hardwareconfiguration that constitutes the projector device 10 together with aCCD camera module constituting the camera unit 22 and a program. Theabove hardware configuration includes a central processing unit (CPU)(processor) that controls operation of the entire projector device 10, aread-only memory (ROM) that stores various kinds of programs executed bythe CPU, a random access memory (RAM) that is used as a work area of theCPU, and a storage device (for example, a hard disk drive (HDD), a solidstate drive (SSD), and the like) that stores various kinds of data suchas a program for the projector device, and the like. In FIG. 3, an arrowin a thick solid line indicates a flow of data such as image data, andan arrow in a thin solid line indicates control data (command data andthe like).

To the video-signal input-processing unit 13, various kinds of inputterminals such as an HDMI (registered trademark) terminal 32, a VGAterminal 33, and a component signal terminal 34 are connected. Throughthese input terminals, a digital signal such as an HDMI (registeredtrademark) signal, an analog signal such as a VGA signal, and an analogsignal such as an RGB component video signal are input to thevideo-signal input-processing unit 13 from an external device or thecamera unit 22 connected to respective input terminals. As one example,when an input video signal is a digital signal, the video-signalinput-processing unit 13 converts the signal into a bit format definedby the video processing unit 12, according to the number of bits of theinput signal. Furthermore, when an input video signal is an analogsignal, the video-signal input-processing unit 13 performsanalog-to-digital conversion (ADC) processing and the like to performdigital sampling of the analog signal, and inputs a signal in an RGB ora YPbPr format into the video processing unit 12. Moreover, to thevideo-signal input-processing unit 13, image data of a projection imagethat is shot by the camera unit 22 is also input.

The video processing unit 12 performs digital image processing and thelike according to an input signal. Specifically, appropriate imageprocessing according to contrast, brightness, chroma, hue, RGB gain,sharpness, a scaler function to scale up and down and the like, andcharacteristics of the drive control unit 14 is performed. The inputsignal subjected to the digital image processing is sent to the drivecontrol unit 14. Furthermore, the video processing unit 12 can alsogenerate an image signal in a layout arbitrarily specified, orregistered. The video processing unit 12 also generates an image signalin a projection pattern (image pattern for projection conversion)indicated in FIG. 4. As an example of a projection pattern that isprojected when a projection conversion coefficient is calculated, a gridpattern, a circle pattern, or the like may be used other than the oneindicated in FIG. 4.

The drive control unit 14 determines driving conditions for the colorwheel 5 to color white light according to the input signal, the imageforming unit 2 that selects light to be emitted and discarded, and thelamp power source 17 that controls a drive current of a lamp, and sendsan instruction to drive to the motor 18 that drives to rotate the colorwheel 5, the image forming unit 2, and the lamp power source 17. Thedrive control unit 14 controls the color wheel 5 to generate colorssequentially.

The drive control unit 14 sends an instruction to shoot to the cameraunit 22 according to a synchronization signal in timing of imageprojection. The shoot timing through the camera unit 22 is describedlater. Although in the present embodiment, the drive control unit 14also serves as the shoot control unit (shoot control unit), each of thecomponents may be arranged independently. When an image shot by thecamera unit 22 is input to the video-signal input-processing unit 13,the video-signal input-processing unit 13 performs shading correction,Bayer conversion, color correction, and the like on a shot camera imageto generate an RGB signal.

The drive control unit 14 further shoots a projection pattern(projection image) projected on the screen from the projector device 10using the camera unit 22, and performs processing to calculate aprojection conversion coefficient from displacement between coordinateson the projection pattern (projection image) and coordinates on theimage data, and processing to detect an irradiation point of a laserbeam from the laser pointer 40. Details of the processing performed bythe drive control unit 14 are explained later.

The camera unit 22 includes a CCD camera module as described above, andshoots a scene in which the projection pattern indicated in FIG. 4 isprojected. As a shooting mode of the camera unit 22, a global shuttermode and a rolling shutter mode are applicable. In the global shuttermode, exposure thereof is performed simultaneously for all pixels, andalthough a more complicated circuit than that of the rolling shuttermode is necessary for each of the pixels, there is an advantage that allof the pixels are exposed at once to perform shooting. In the rollingshutter mode, a sequential scanning type of exposure is performed, andimplementation is possible with simple circuits, and shooting can beperformed in a scanning form. However, because shooting timing differ ineach pixel, distortion and the like can occur when an object moving athigh speed is imaged. The shutter speed of the camera unit 22 isdesirable to be controlled by the drive control unit 14. The drivecontrol unit 14 controls by determining the shutter speed required forshooting in timing and in time specified by a synchronization signal,for example, based on the rotation speed of the color wheel, to performcontrol.

The conversion processing unit 25 performs projection conversion fromcoordinates of an irradiation point (x′, y′) into coordinates on imagedata (x, y) using a projection conversion coefficient H that iscalculated by the conversion-coefficient calculating unit 26 describedlater.

When image data of a projection image shot by the camera unit 22 isinput, the conversion-coefficient calculating unit 26 calculates theprojection conversion coefficient H that associates coordinates on avideo signal of the projection pattern (x, y) and coordinates on theshot image (x′, y′) based on data of a shot image, and sets theprojection conversion coefficient H in the conversion processing unit25.

The pointer generating unit 27 generates irradiation-point image data(emphasizing image data) at the coordinates (x, y). Theirradiation-point image data is, for example, a circular shape imagehaving a radius of z pixel length at the coordinates (x, y) in center(that is, data of a box described above, a pointer image that isregistered in advance, an underline, or the like may be generated in anarbitrary generation method). The pointer generating unit 27 performsthese calculations, and generates a projection image signal to send tothe video processing unit 12.

Explanation returns to the video processing unit 12 again. The videoprocessing unit 12 superimposes a video signal that is generated by thepointer generating unit 27 on the video signal and performs arbitraryimage processing thereon, and then sends the signal subjected to theimage processing to the drive control unit 14. When the signal subjectedto the image processing is output to the drive control unit 14, thedrive control unit 14 controls the image forming unit 2, the lamp powersource 17, and the motor 18 based on the signal subjected to the imageprocessing described above, and the projection image on which thepointer image is superimposed is projected from the projection system 3b.

Next, details of processing of detecting coordinates of a pointer thatis irradiated on a projection surface performed by the irradiation-pointdetecting unit 24 are explained. In FIG. 5, filter segments in variouscolors constituting a color wheel, namely, filter segments (areas) ofseven colors of Cy (cyan)-W (white)-R (red)-M (magenta)-Y (yellow)-G(green)-B (blue), for example, are illustrated. Hereinafter, a filtersegment is described simply as segment or color segment.

Moreover, in FIG. 6, correlation between seven segments of a color wheeland a camera shot image when each segment is displayed on a projectionsurface, that is, RGB data. The drive control unit 14 performs controlto make light pass through areas of colors of the color wheel 5 that aredetermined according to color of light of the input image data in a timeunit, to realize color of the image data. For example, in the Redsegment, transmittance of light in Red (R) (wavelength component) ishigh and data of Red (R) makes up most in the RGB data also, whiletransmittance of Green (G) and Blue (B) is low and light in these colorsare limited.

Similarly, in a Green segment, data of Green (G) makes up most, andlight in Blue (B) and Red (R) (wavelength component) is limited.Similarly, in a Blue segment, data of Blue (B) makes up most, and lightin Green (G) and Red (R) (wavelength component) is limited.

Moreover, a Cyan segment, a Magenta segment, and a Yellow segment ofsecondary colors pass light of Blue and Green, light of Blue and Red,light of Green and Red, respectively. Furthermore, a White segment of atertiary color passes light of all of RGB.

In FIG. 7A, relationship between the seven color segments of the colorwheel 5 and projection light colors is indicated. Light from the lightsource is irradiated in the entire area of the seven color segments in acircumferential direction while the color wheel 5 rotates once. Thelight color is a concept that includes both color of light of the lightsource itself and color of light visually recognized from light emittedfrom the light source. It is indicated that a section of a periodindicated by a solid line arrow in FIG. 7A is an area in which an imagesignal is projected through the corresponding segment of the color wheel5 in the color thereof.

For example, focusing on the projection light color Red, components thatare categorized as Red are sections of the Red segment, the Magentasegment, and the Yellow segment, and a section of the White segment. Onthe other hand, a section indicated by a broken line arrow of Timing Ais a section in which an optical image corresponding to a Red videosignal is not projected. That is, in the sections corresponding to theGreen segment, the Blue segment, and the Cyan segment of the color wheel5 corresponding to the section of this Timing A, even if the projectionlight color is Red, because an optical image actually corresponding to avideo signal is not projected, even a red laser beam from a laserpointer becomes easy to be detected. Similarly, in sectionscorresponding to respective color segments of the color wheel 5corresponding to a section of Timing B and a section of Timing C, alaser beam in green and a laser beam in blue from a laser pointer becomeeasy to be detected, respectively.

Accordingly, in the present embodiment, when a laser pointer thatirradiates red laser beams (hereinafter, red laser pointer) is used asthe laser pointer 40, in detection of a position of an irradiation pointof the laser beam, shooting and detection of a red laser beam(irradiation image) that is irradiated on the screen 30 are performedduring Timing A.

However, if start and end of the section of Timing A and shooting timingby the camera unit 22 are completely synchronized, leakage light from anadjacent color segment, for example, the Yellow segment or the Redsegment, can affect a shooting result of the camera unit 22. Moreover,aged deterioration, specifically, deterioration of a lens or a sensorequipped in the camera unit 22 caused by heat (inaccurate shootingtiming, variation in chromaticness, and the like), deterioration ofcolor segments of the color wheel 5 (variations in chromaticness, andthe like), and delay of electric signals because of aging of electricparts, and the like can occur.

Therefore, in the present embodiment, timing (exposure time) in whichthe camera unit 22 images a projection surface on which a red laser beamis irradiated is set to a period, for example, from a point of timedelayed by a certain amount of time from start of Timing A to a point oftime earlier by a certain amount of time than end of Timing A, as setexposure time 1 and set exposure time 2 indicated in FIG. 7B. Asindicated in the set exposure time 1 and the set exposure time 2, whenthe irradiation point of the red laser beam is detected, the camera unit22 is set such that exposure time (shooting time) is a period (time)between a point of time when a certain amount of time has passed from anend point of Yellow and a point of time earlier by a certain amount oftime than a start point of White in segments of the color wheel 5(therefore, color of the projection light colored through the segment).As long as shooting is performed within this period (time), the shutterspeed can be arbitrarily selected (set).

Similarly, when a laser pointer that irradiates green laser beams(hereinafter, green laser pointer) is used as the laser pointer 40, indetection of a position of an irradiation point of the laser beam,shooting timing (exposure time) of the camera unit 22 is set to a periodfrom a point of time delayed by a certain amount of time from start ofTiming B to a point of time earlier by a certain amount of time than endof Timing B. That is, it is set such that a period (time) between apoint of time when a certain amount of time has passed from an end pointof White and a point of time earlier by a certain amount of time than astart point of Yellow, or a period (time) between a point of time when acertain amount of time has passed from an end point of Green and a pointof time earlier by a certain amount of time than a start point of Cyanis the exposure time (shooting time). As long as shooting is performedwithin this period (time), the shutter speed can be arbitrarily selected(set).

Similarly, when a laser pointer that irradiates blue laser beams(hereinafter, blue laser pointer) is used as the laser pointer 40, indetection of a position of an irradiation point of the laser beam,shooting timing (exposure time) of the camera unit 22 is set to a periodfrom a point of time delayed by a certain amount of time from start ofTiming C to a point of time earlier by a certain amount of time than endof Timing C. That is, it is set such that a period (time) between apoint of time when a certain amount of time has passed from an end pointof White and a point of time earlier by a certain amount of time than astart point of Magenta, or a period (time) between a point of time whena certain amount of time has passed from an end point of Magenta and apoint of time earlier by a certain amount of time than a start point ofBlue is the exposure time (shooting time). As long as shooting isperformed within this period (time), the shutter speed can bearbitrarily selected (set).

FIG. 8 indicates image data when laser beams from red, green, and bluelaser pointers are irradiated on one projected image. Furthermore, FIG.9 indicates images of detected irradiation points of laser beams fromlaser pointers when a projected image on which laser beams from red,green, and blue laser pointers are irradiated in Timing A, B, and C isshot. For example, Timing A Red Shot Image in FIG. 9 shows one exampleof image data that is acquired by shooting the screen 30 during thesection of Timing A by the camera unit 22.

In the example of FIG. 9, the shooting timing of the camera unit 22 issynchronized with timing in which the drive control unit 14 drives thecolor wheel 5. For example, when the camera unit 22 detects a positionof an irradiation point of a laser beam from the red laser pointer, andwhen shooting is performed in Timing A, because a the color wheel 5 isrotated at a fixed frequency (120 Hertz (Hz) in the present embodiment),a synchronization signal to control the shooting time of the camera unit22 is set by the drive control unit 14 in timing in which the colorwheel 5 corresponds to a predetermined period in Timing A.

In the section of Timing A, light corresponding to a Red video signal iscertainly not irradiated, and therefore, detection of an irradiationpoint of a laser beam from the red laser pointer becomes easy.Accordingly, when irradiation light (laser beam) from the red pointer isdetected, based on the above synchronization signal, shooting performedby the camera unit 22 is synchronized to a predetermined period inTiming A. Thus, detection accuracy of an irradiation point of a laserbeam from the red laser pointer, and further, detection accuracy of aposition of the irradiation point are improved.

Similarly, in Timing B Green Shot Image in Timing B, light correspondingto a Green video signal is not irradiated, and therefore, detectionaccuracy of an irradiation point and a position thereof of a laser beamfrom the green laser pointer is improved. Furthermore, in Timing C BlueShot Image in Timing C, light corresponding to a Blue video signal isnot irradiated, and therefore, detection of an irradiation point of alaser beam from the blue laser pointer becomes easy. As described, thereis a color that is easy to be detected depending on timing, and byeffectively using each Timing, irradiation points of laser beams inmultiple colors can be detected at the same time.

Next, a method of synchronizing shooting by the camera unit 22 todriving of the color wheel 5 is explained. The drive control unit 14acquires a detection signal of a predetermined position from the markersensor 19 described above, and relative to detection timing thereof,generates (or, instructs a synchronization-signal generating unit notshown to issue) the synchronization signal to control shooting timing ofthe camera unit 22. The synchronization signal to control shootingtiming of the camera unit 22 is different from the synchronizationsignal to control the color wheel 5 according to a video signal (imagesignal) generated based on a vertical synchronization signal in thevideo signal (image signal).

The generated synchronization signal is determined so as to synchronizewith a predetermined period within a period in which light in colorclosest to the color of the set laser pointer is not projected. Thus,the camera unit 22 is enabled to control shutter timing for shootingrelative to the detection signal from the marker sensor 19 that detectsa predetermined rotation position of the color wheel 5. The color of alaser pointer is set, for example, by inputting through an interface(not shown) for operating the projector device 10 by a user.

In FIG. 10 and FIG. 11, one example of relation among a rotation cycleof the color wheel, a shooting cycle, and shutter/exposure timing of thecamera unit 22 is indicated. For example, the color wheel 5 rotates in acycle of 120 Hz, and the camera unit 22 shoots the screen 30 in a cycleof 30 Hz. In this example, while the color wheel 5 rotates four times,the camera unit 22 shoots once. In FIG. 10, an example ofshutter/exposure timing when rotation of the color wheel 5 and shootingare synchronized in the case of a laser beam irradiated from the laserpointer 40 including color of red is indicated. In FIG. 10, it issupposed that a section of C is a blank period of Red, that is, apredetermined section (for example, the set exposure time 1 in FIG. 7Bdescribed above) in Timing A (corresponding to Green, Blue, and Cyan ofthe color wheel 5). In this case, the camera unit 22 exposes to one ofthe sections of C in the first cycle to shoot an image, thereby enablingdetection of an irradiation point of a laser beam from the red laserpointer by observing an image shot at this time.

Usually, light is irradiated on the screen 30 when the image formingunit 2 is ON, and not irradiated when OFF. However, in the aboveexample, by performing shooting in synchronization to correspondingtiming even when ON, an irradiation point can be detected from colordata of either one of RGB. In other words, an irradiation point from thelaser pointer 40 can be detected independent of contents of video.

FIG. 11 indicates a synchronization method when a laser pointer hasmultiple colors. The camera unit 22 exposes to one of sections of A inthe first cycle to shoot an image. The section of A in this example is asection corresponding to a predetermined section in Timing A, and byobserving image data shot in this timing, an irradiation point of alaser beam from the Red laser pointer can be detected. The camera unit22 exposes to a section of B in the second cycle to shoot an image. Thesection of B is a section corresponding to a predetermined section inTiming B, and by observing image data shot in this timing, anirradiation point of a laser beam from the Green laser pointer can bedetected. The camera unit 22 exposes to a section of C in the thirdcycle to shoot an image. The section of C is a section corresponding toa predetermined section in Timing C, and by observing image data shot inthis timing, an irradiation point of a laser beam from the Blue laserpointer can be detected.

Similar control is performed thereafter, and irradiation points of red,green, and blue are sequentially detected. In the above case, thesynchronization signal includes three kinds of timing of thepredetermined section in Timing A in the first cycle, the predeterminedsection in Timing B in the second cycle, and the predetermined sectionin Timing C in the third cycle. When more than one pointer in the samecolor is used, irradiation point are detected as multiple points in ascreen, and therefore, detection can be achieved without problems.

Next, calculation of the projection conversion coefficient performed bythe projector device 10 according to the present embodiment and a flowin processing of detecting a laser pointer are explained based on FIG.12. FIG. 12 is a flowchart indicating a process algorism of the drivecontrol unit 14 of the projector device 10. The processing correspondingto the flow chart in FIG. 12 is performed in a unit of one frame of aninput video signal.

When this flowchart starts is, as one example, when the external PC 20is connected to the projector device 10 through a cable and when powerof the projector device 10 is turned on.

First, at step S101, the drive control unit 14 performs processing toproject a video signal from an input interface (I/F) of a video signalthat is input through either one of the input terminals 32, 33, and 34described above (step S101). This processing includes control to drivethe motor 18 that drives to rotate the color wheel 5 according to avideo signal, the image forming unit 2, and the lamp power source 17.

At following step S102, the drive control unit 14 determines whether ornot an irradiation-point detection mode is set. The irradiation-pointdetection mode is a mode in which an irradiation point of a laser beamthat is irradiated to the screen 30 by the laser pointer 40 is detected,for example. The irradiation-point detection mode is, as one example,activated by operating an operation screen or a button of the projectordevice 10 when a user uses the laser pointer 40 and the like. Whennegative determination is made at step S102, in other words, when it isdetermined that it is not in the irradiation-point detection mode, theprocess returns to step S101. The processing thus shifts to a next frameof the video signal. Until positive determination is made at step S102,in other words, until the irradiation-point detection mode is set, theprocessing and determination at steps S101 and S102 are repeated.

On the other hand, when positive determination is made at step S102, inother words, when it is determined that the irradiation-point detectionmode is set, the drive control unit 14 determines whether or not it isin an initial setting mode at step S103. The initial setting mode is amode in which the projection conversion coefficient is calculated when aprojection environment changes, and when the irradiation-point detectionmode is first activated, it is set in the initial setting mode. Forexample, a flag dedicated to the initial setting mode is prepared, andwhen the flag is not raised (reset), it is determined as the initialsetting mode, and raising the flag or the like is considered. Other thanthis, whether or not it is in the initial setting mode may be determinedbased on whether or not the projection conversion coefficient has beenset, whether or not a predetermined time has passed since the projectionconversion coefficient is set, or the like. The projection conversioncoefficient is a coefficient to correct displacement between an imagesignal before projection and coordinates of an image pattern whenprojected.

When positive determination is made at step S103, in other words, whenit is determined as the initial setting mode, the drive control unit 14drives the image forming unit 2 and the like, at step S104, to projectan image pattern (see FIG. 4) for projection conversion generated by thevideo processing unit 12 on the screen 30 (step S104).

At following step S105, the drive control unit 14 instructs the cameraunit 22 to shoot the projection area 35 on the screen 30 on which theimage pattern described above is projected. This shooting is performedby the camera unit 22 according to an instruction by the drive controlunit 14.

At following step S106, the drive control unit 14 instructs theconversion-coefficient calculating unit 26 to calculate the projectionconversion coefficient. This calculation of the projection conversioncoefficient is performed by the conversion-coefficient calculating unit26 as follows. That is, the conversion-coefficient calculating unit 26measures displacement between coordinates of an image pattern that isshot by the camera unit 22 and input through the video-signalinput-processing unit 13 and coordinates of the irradiated image patternin data, and calculates the projection conversion coefficient so thatthe coordinates of these two data coincide with each other. Thecalculated projection conversion coefficient is stored, process proceedsto step S103. Here, the sequential process of steps S103, S105, and S106is implemented in a small amount of time shorter than the time forprocessing one flame of the image signal.

On the other hand, when negative determination is made at step S103, inother words, when it is determined that it is not in the initial settingmode, process proceeds to step S107, and the drive control unit 14instructs the camera unit 22 to shoot the projection area 35 on thescreen 30. At this time, a laser beam from the laser pointer 40 isirradiated on the screen 30 together with video that is projected atstep S101. This shooting at step S107 is performed by the camera unit 22according to the synchronization signal for shooting that is transmittedfrom the drive control unit 14 in timing described previously.

At following step S108, the drive control unit 14 instructs theirradiation-point detecting unit 24 to detect an irradiation point. Theshooting timing at step S107 described above is determined according toirradiated color of the laser pointer. Therefore, the irradiation-pointdetecting unit 24 can detect an irradiation point of a laser beam fromthe laser pointer 40 based on shot image data.

At following step S109, the drive control unit 14 instructs theconversion processing unit 25 to perform projection conversion of thedetected irradiation point. That is, coordinates of the detectedirradiation point are input to the conversion processing unit 25, andthe conversion processing unit 25 performs projection conversion on thecoordinates of the irradiation point into coordinates on image datausing the projection conversion coefficient calculated by theconversion-coefficient calculating unit 26 and stored.

At following step S110, the drive control unit 14 instructs the pointergenerating unit 27 to generate a pointer, that is, a pointer image(irradiation-point display image) to the irradiation point after theprojection conversion. The pointer generating unit 27 generates, basedon data of the coordinates acquired by performing the projectionconversion from the conversion processing unit 25, image data of apointer to be displayed at the position corresponding to the coordinatesin original video signal data.

At following step S111, the drive control unit 14 instructs the videoprocessing unit 12 to combine the video signal with the image data of apointer. According to an instruction, projection image data to which apredetermined image is added according to the position of the detectedirradiation point is generated by the video processing unit 12.

Thereafter, the process returns to step S101. As a result, while theirradiation-point detection mode is set, even if a presenter operatesthe laser pointer 40 and moves the pointed point (irradiation point),display with the pointer image moved according to the movement thereofis enabled.

As data of the emphasizing image that is generated at above step S110and combined to data of a video signal at step S111, in addition to thepointer image described above, to improve the visibility thereof, forexample, a ring-shaped image (one of the emphasizing images) thatsurrounds the calculated irradiation point in center may be displayed asillustrated in FIG. 13, or a circular image indicating the irradiationpoint may be projected in such a manner that the radius thereof isenlarged with the calculated irradiation point in center. In this case,the pointer is enlarged, and therefore, the pointer becomes more easilyviewable. As the emphasizing image, an underline or a box describedabove may be displayed. In addition to this, as illustrated in FIGS.14(a) and 14(b), an area of a part of image data therearound relative tothe coordinates of the calculated irradiation point is displayed in anenlarged manner to be projected, instead of enlarging the pointer. Suchenlarged display and the like are performed, in the present embodiment,by the drive control unit 14 using the video processing unit 12 toprocess image data of a projection object as a part of image processing.

As it is obvious from the above explanation, in the present embodiment,a projecting unit is configured with the image forming unit 2, theoptical system 3 a, the projection system 3 b, the light source 4, thevideo processing unit 12, the drive control unit 14, the lamp powersource 17, and the motor 18 included therein. Moreover, aprojection-image generating unit is configured with the pointergenerating unit 27 and the video processing unit 12 included therein.

Although in the above embodiment, an example in which when laser beams(irradiation points thereof) from laser pointers of multiple colors aredetected, the laser beams in multiple colors are detected by a singleunit of camera has been explained, it is not limited thereto, and acamera may be equipped for each color to be detected, and detectioncontrol may be performed for each color. With such a configuration, timein which a shooting task of the camera unit 22 is not occupied by othercolors is eliminated, and a detecting section of each color can bereduced. In this case, it is preferable that which timing corresponds toeach of the camera units 22 be set in advance. That is, for example,when three units of camera units are arranged corresponding to threecolors of RGB, an irradiation point of a laser pointer of each color canbe detected in each cycle.

Furthermore, besides the above, when an intermediate color is desired tobe detected, regions of Timing A, B, and C may be divided furtherprecisely for each color. In this case, by shooting in timingcorresponding to intermediate color desired to be detected, detection isenabled for each segment of the color wheel 5.

Although in the above embodiment, the camera unit 22 is arranged in theprojector device 10, it is not limited thereto, and for example, acamera unit 22′ as the camera unit 22 may be detachably arranged asillustrated in FIG. 15. Alternatively, a CCD camera or the like thatconstitutes the camera unit 22 separately from the projector device 10and the external PC may be arranged as a shooting unit. Moreover,although in the above embodiment, a case in which the drive control unit14 of the projector device 10 serves as the shoot control unit also hasbeen explained, it is not limited thereto, and the external PC 20 mayhave a function of controlling the camera unit 22. That is, the shootcontrol unit may be arranged in the external PC. Furthermore, a part ofvarious kinds of functions of the drive control unit 14 in the projectordevice 10 may be implemented by another control device, or by theexternal PC. Accordingly, in the presentation system according to thepresent invention, it is only required to include the shoot controlunit, a position detecting unit, and the like as components thereof.

Moreover, although in the above embodiment, a case in which setting ofthe irradiation-point detection mode is performed by operating anoperation screen or a button of the projector device 10 by a user hasbeen exemplified, it is not limited thereto, and such a configurationthat an irradiation device such as a laser pointer and the projectordevice 10 are connected by a wireless line (or wired line), and power-onand off are detected by the drive control unit 14 (the shoot controlunit) of the projector device 10 through wireless or wired communicationmay be applied.

Furthermore, although in the above embodiment, a case in which theprojector device 10 is of the DLP type using a color wheel has beenexplained, it is not limited thereto, and the present invention can beapplied also to, for example, a projector device through a liquidcrystal display panel referred to as a field sequential type or apresentation system that includes a projector device.

It may be configured such that a program (for example, program to makethe CPU execute the processing algorithm corresponding to the flowchartin FIG. 12) that is executed by the projector device 10 of the aboveembodiment is recorded on a computer-readable recording medium such as acompact-disc read-only memory (CD-ROM), a flexible disk (FD), acompact-disc recordable (CD-R), and a digital versatile disk (DVD), in afile in an installable format or an executable format, to be provided.

Moreover, it may be configured such that a program that is executed inthe projector device of the present embodiment is stored in a computerthat is connected to a network such as the Internet, and is provided bybeing downloaded through the network. Furthermore, it may be configuredsuch that a program that is executed in the image projection apparatusof the present embodiment is provided or distributed through the networksuch as the Internet.

A program that is executed in the image projection apparatus of thepresent embodiment has a module configuration including the respectivecomponents described above, and the respective components are loaded ona main storage device by reading and executing the program from theabove ROM by a CPU (processor) as actual hardware, thereby generatingthe respective components on the main storage device. Furthermore, eachcomponent in the projector device 10 may be implemented as software by aprogram, or as hardware with combination of predetermined electroniccircuits.

The image projection apparatus of the present invention produces such aneffect that an irradiation point of light from an irradiation device canbe stably detected.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. An image projection apparatus comprising: a projecting device that projects and displays on a projection surface each image in a time sharing manner for each of a plurality of color components, for an input image signal, wherein the projecting device includes a color wheel having a plurality of different color filters that are used to project the plurality of color components; an image capturing device that captures a projected image on the projection surface; and circuitry configured to: detect, on the projection surface, a color of an irradiation point irradiated from an irradiation device; determine a timing with respect to one of the plurality of color components based on the detected color of the irradiation point, the determined timing representing a timing in which the one of the plurality of color components is not projected by the projecting device; set a period of exposure time in relation to the plurality of different color filters, the set period of exposure time being set to a period from a point of time delayed from a start of the determined timing to a point of time earlier than an end of the determined timing; and detect a position of the irradiation point based on the capturing of the projected image during the set period of exposure time.
 2. The image projection apparatus according to claim 1, wherein the plurality of color filters are arranged on an identical circumference in sections and pass light from a light source, and the circuitry is further configured to: detect a rotation position of the color wheel, and control the image capturing device to perform the capturing based on the detected rotational position.
 3. The image projection apparatus according to claim 2, wherein the circuitry is further configured to set a shutter timing along with the set period of exposure time.
 4. The image projection apparatus according to claim 1, wherein the circuitry is further configured to perform an image processing to display a predetermined emphasizing display image at the detected position of the irradiation point, or perform an image processing to display an image corresponding to image data in a part of an area around the detected position of the irradiation point in an enlarge manner.
 5. The image projection apparatus according to claim 1, wherein the circuitry is further configured to: detect a plurality of different colors of the irradiation device.
 6. The image projection apparatus according to claim 1, further comprising: additional image capturing devices, wherein the circuitry is configured to control the image capturing device to perform the capturing or the additional image capturing devices to perform capturing of a projected image, based on the detected color.
 7. A presentation system comprising: a projecting device that projects and displays on a projection surface each image in a time sharing manner for each of a plurality of color components, for an input image signal, wherein the projecting device includes a color wheel having a plurality of different color filters that are used to project the plurality of color components; an image capturing device that captures a projected image on the projection surface; a irradiation device that forms an irradiation point by irradiating light onto the projection surface; and circuitry configured to: detect, on the projection surface, a color of the irradiation point irradiated from the irradiation device; determine a timing with respect to one of the plurality of color components based on the detected color of the irradiation point, the determined timing representing a timing in which the one of the plurality of color components is not projected by the projecting device; set a period of exposure time in relation to the plurality of different color filters, the set period of exposure time being set to a period from a point of time delayed from a start of the determined timing to a point of time earlier than an end of the determined timing; detect a position of the irradiation point based on the capturing of the projected image during the set period of exposure time.
 8. The presentation system according to claim 7, wherein the circuitry is further configured to determine whether or not a detection mode of the irradiation device is set, by detecting power-on and off of the irradiation device by any one of wireless and wired communication. 